Among these substances, the group of Freons, such as Freon R12, R22, R512, F11, and so forth, make up a very large proportion. In their free state, these halogenated hydrocarbons, in particular chlorinated fluorocarbons, are one of the primary causes for the destruction of the ozone layer in the atmosphere. These toxic substances are liberated when spray cans are used, for instance, or in the manufacture of plastics.
The most recent figures for the Federal Republic of Germany indicate that 2.3 million household refrigerators and freezers are disposed of annually as trash, or are taken to garbage dumps and scrap dealers. As a rule, the refrigerating cycle is destroyed in this process, so approximately 350 metric tons of refrigerants of the above type escape into the atmosphere each year and contribute to the destruction of the ozone layer. In addition, approximately 900,000 liters of used oil leak out of the refrigerator compressors into the ground every year. Other systems however, such as large refrigeration plants or heat pumps, also contribute in this way to the environmental burden.
Attempts are therefore now being made to regulate the disposal of such systems and equipment by law. Refrigerators, for instance, are to be collected separately. Prior to the final dismantling or scrapping, the refrigerant and the used oil are to be collected and re-used after processing.
In some known methods for disposing of the refrigerant, the refrigerant is simply aspirated from the refrigeration cycle and collected in containers in the gaseous state. These methods have the disadvantage, however, that it takes up to nine hours to aspirate the refrigerant from a single refrigerator. A further disadvantage of these methods is that very large containers must be used to collect the gaseous Freon.
Other methods are also known, for instance from German Patent 30 01 224, in which the refrigerant is extracted from the refrigeration system by means of a compressor and supplied in liquid form to a pressure vessel. This vessel is connected to a weight switch, which switches off the delivery of any further refrigerant once a predetermined total weight is attained. For performing this method, an apparatus is used that is either portable or transportable on a vehicle. A major disadvantage of the previously known system is that it requires a great number of manually actuated valves to control the drainage process. Malfunction-free operation of the system can be done only by carefully trained persons. A further disadvantage is the fact that the recovered refrigerant is highly contaminated, not only by foreign substances such as oil and water that had already been absorbed in the refrigeration cycle, but also by oil and dirt from the compressor in the recovery system. The contaminated refrigerant can then either be reprocessed, which is expensive, or it must be destroyed. If it is to be destroyed, very high temperatures must be generated for combusting the refrigerant; otherwise, the dioxides and other toxic substances that are produced will be liberated. Similar methods and apparatus, having the same disadvantages, are known for instance from German Utility Model 87 08 522 or German Published, Non-Prosecuted Application 36 16 591. In connection with German Utility Model 87 08 522, it should also be noted that in that system, an oil separator is disposed downstream of the compressor; the oil separator is intended for removing oil from the refrigerant to be recovered, and the oil is returned to the compressor. The contaminated refrigerant already in the refrigeration system accordingly reaches the compressor in an uncleaned state, which can damage or even destroy the compressor. The recovered refrigerant from which the oil has been removed still includes other contaminants, however, which prevent immediate re-use of the refrigerant.